On Thu, Aug 05, 2010 at 03:13:03PM +0900, KOSAKI Motohiro wrote: > congestion_wait() mean "waiting quueue congestion is cleared". > That said, if the system have plenty dirty pages and flusher thread push > new request to IO queue conteniously, IO queue are not cleared > congestion status for long time. thus, congestion_wait(HZ/10) become > almostly equivalent schedule_timeout(HZ/10). > > However, synchronous lumpy reclaim donesn't need this > congestion_wait() at all. shrink_page_list(PAGEOUT_IO_SYNC) are > using wait_on_page_writeback() and it provide sufficient waiting. > > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> Needs rebasing for mmotm but otherwise; Acked-by: Mel Gorman <mel@xxxxxxxxx> > --- > mm/vmscan.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index cf51d62..1cdc3db 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1341,7 +1341,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone, > > /* Check if we should syncronously wait for writeback */ > if (should_reclaim_stall(nr_taken, nr_reclaimed, priority, sc)) { > - congestion_wait(BLK_RW_ASYNC, HZ/10); > /* > * The attempt at page out may have made some > * of the pages active, mark them inactive again. > -- > 1.6.5.2 > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>